1. Field of the Invention
The present invention relates to a vehicles movement measuring apparatus which is placed above a road and measures and collects traffic data about the road regarding the number of vehicles passing below the apparatus, speeds of such vehicles, the types thereof (e.g. compact cars or large size cars), and further necessary information.
2. Description of the Related Art
A conventional vehicles movement measuring apparatus measures and outputs data regarding the number of vehicles passing below the apparatus, speeds of such vehicles, the types thereof (e.g. compact cars or large size cars), etc., by taking images of the motor vehicles, their attitudes and the background, and image-processing the original vehicle image data and the background image data.
Such an apparatus is disclosed in Japanese Patent Unexamined Publication Nos. 2-158899 and 2-284297.
However, such a conventional vehicles movement measuring apparatus can only determine the number of passing motor vehicles, their speeds and the vehicle types; it does not detect the degree of traffic jams on the road. Thus, the conventional apparatus is not satisfactory in the measuring of vehicles attitudes.
Also, since the conventional apparatus can only determine the number of passing motor vehicles, their speeds and the vehicle types, the conventional vehicles movement measuring apparatus can not detect how heavy the traffic is on the road ahead, which is also important information. For example, this information is important where the output of vehicle sensors is used to determine the output timing of traffic signal controllers located at an intersection of roads. Conventionally, only data regarding the traffic upstream from the intersection is used. Therefore, if the road downstream from the intersection is congested, the output timing for green lights thus determined becomes useless.
Since the conventional vehicle sensors only detect and collect data of the upstream traffic, sensors must be provided at a plurality of locations if there is a need for data on the traffic downstream from an intersection as well. However, it is not possible to provide sensors at all of the desired locations, because of local conditions or on account of considerations of townscape or landscape beauty.